Autoplastic transplantation of parathyroid tissue has been practiced by a number of surgeons in connection with operations on the thyroid gland when one or more parathyroid glandules have been accidentally removed. This procedure has been advocated, particularly by Lahey, as a means of preventing the occasional occurrence of postoperative tetany. As far as we are aware, however, there has been no final proof of the survival of the transplant in these cases. Cattell1 observed post-operative tetany in one of his patients in whom parathyroid tissue had been reimplanted between the fibers of the sternocleidomastoid muscle. The facts that the calcium content of the blood gradually returned to normal in the course of several weeks and that the tetany spontaneously and permanently disappeared were taken to indicate that the transplant had survived and was functionally active. There was no opportunity, however, to check this by microscopic study.